Thermal tiles are installed on space vehicles, such as the Orbiter, to protect the space vehicle from overheating during reentry into the Earth's atmosphere. Such tiles are usually installed in such a way that gaps are maintained between each tile on the vehicle. However, high pressure gradients can exist along the vehicle surface and adverse thermal effects may then result from the flow of gasses through these gaps, particularly during reentry through the Earth's atmosphere. To minimize adverse gap heating, gap fillers are presently installed in these critical gaps during vehicle assembly after the tiles have been installed. Gap fillers may also be installed at any time after vehicle assembly when additional critical areas are identified.
Gap fillers may be made of various materials and configurations. An example of such a gap filler may be seen in U.S. Pat. No. 4,308,309. Currently, such gap fillers are secured by bonding them with room temperature vulcanizing (RTV) polymer to the filler bar located underneath and between the tiles. RTV, e.g. composition of silicone rubber, is placed between the tiles along the filler bar and then the gap filler is inserted between the tiles to form a bond. This type of installation is described in the aforementioned U.S. Pat. No. 4,308,309.
There is a significant disadvantage associated with RTV installation of gap fillers between tiles. Installing the gap filler with RTV is an operation which is difficult to perform properly in a time efficient manner. RTV is often smeared along the sides of the tiles because the gaps are small, e.g. 0.030 to 0.060 inches. During ascent and reentry of the space vehicle to which the tiles and gap fillers are attached, high tile temperatures causes the RTV to burn off the sides of the tiles and the RTV no longer provides an adequate bond to the vehicle. This is why the gap filler is intended to be bonded to the filler bar instead of the tile. As the gap fillers are currently installed, it is difficult to verify whether the gap filler is being held in place by an RTV bond to the side of the tiles or by a bond established with the filler bar. Since the structural integrity of each installation is unreliable, as described above, many gap fillers have become detached and lost during flight. As a result, increased heating of the vehicle may occur, increasing the possibility of large scale structural repair.
Thus, the current methods of installing gap fillers in the gap between tiles or, for that mutter, installing any structure in gaps or narrow spaces, are not satisfactory for many applications. Retaining apparatus and methods for such gap fillers can be improved in reliability, installation time, and structural integrity.